Cover the portion of the wall that will have stone veneer attached with a layer of felt paper and wire mesh to serve as a base for the concrete. Cut the felt paper with a utility knife and staple it to the wall with the hammer tacker, and then cover the felt paper with a layer of wire mesh, which you also staple on. Cut the wire mesh with the tin snips.
Mix concrete mortar in the wheelbarrow according to manufacturer's instructions. Stir it with a shovel and add enough water until you have a creamy, thick mixture. Shovel some of the concrete into a bucket and use that while you work.
Scoop some mud out of the bucket with your mason trowel and cover the wire mesh in a layer of concrete, ensuring that you force the concrete around the back of the wire mesh, completely encasing it.
Work your way up from the bottom of the garage wall with your stone veneers. Apply at least a 1/2-inch layer of concrete on the backs of every piece. Press them against the wall on top of the wire mesh, which is also covered in concrete. Stack them tight to each other as you work your way up the wall so that you don’t need grout joints, giving you the look of stacked stone. Make any necessary cuts with the tile wet saw.